Bond trading platform eSpeed, which last month elicited a bid from UK interdealer broker Tullett Prebon, has been hit by the expiry of a controversial patent that brought it $40m (â¬29m) in compensation over six years.

The Wagner patent, which was developed to match futures electronically, expired at the end of February. Last week, eSpeed said as a result, it “expects lower revenue and net operating income for the remainder of 2007”.

The group, which reported first-quarter results last week, said the patent accounted for $3.5m in revenues and $1.5m in net income this year. ESpeed, which is controlled by US broker Cantor Fitzgerald, bought the patent from Electronic Trading Systems in 2001. ETS had the patent approved in 1987.

The platform brought eSpeed $48m in licence infringement settlements from exchanges, including the New York Mercantile Exchange, Chicago Mercantile Exchange, Chicago Board of Trade and InterContinental Exchange. Nymex agreed to pay $8m in 2003. The previous year, CME and CBOT each agreed to pay eSpeed $15m over five years.

The loss of the patent could weaken eSpeed’s position as it attempts to fight off takeover bids. Last month, Cantor Fitzgerald rejected a $605m offer from Tullett Prebon. Shortly after, Tullett chief executive, Terry Smith, wrote to minority shareholders in eSpeed to support his group’s offer. Tullett Prebon first bid for eSpeed in 2005.